Causes of Cataracts

Eyes are the windows to our human soul. With eyes, people can enjoy the colorful world, feel the beautiful mountains and rivers of nature, experience the warmth and coldness of the human world, and so on. On the contrary, without eyes, people’s world would be dull and colorless, so people must remember to take care of their eyes while they are busy with life and work. However, even with careful protection, the eyes cannot avoid being infected with diseases, such as myopia, trachoma, cataracts, etc. Among them, cataracts are relatively common and serious eye diseases.

When it comes to cataracts, people may not have any concept about it, and no matching images may appear in their minds. In fact, cataract refers to a disease in which the vision becomes blurred due to external influences or changes in the eye's own conditions. So, what causes cataracts?

This is how cataracts are defined in medicine. Various reasons such as aging, heredity, local nutritional disorders, immune and metabolic abnormalities, trauma, poisoning, radiation, etc. can cause lens metabolism disorders, leading to lens protein denaturation and turbidity, which is called cataracts. At this time, light is blocked by the turbid lens and cannot be projected onto the retina, resulting in blurred vision. It is more common in people over 40 years old, and the incidence rate increases with age.

The clinical manifestations of cataracts are unilateral or bilateral, and the disease may occur in one eye or the other. There is a progressive deterioration of vision. Due to the opacity of the lens cortex, the refractive power of different parts of the lens is different, which may cause glare, monocular diplopia, and increased myopia. Clinically, senile cataracts are divided into three types: cortical, nuclear, and subcapsular.

1. Cortical cataract

The main feature is grayish white turbidity of the lens cortex, and its development process can be divided into four stages: initial stage, immature stage, mature stage, and overmature stage.

2. Nuclear cataract

Lens opacity begins to increase in density from the center of the lens, where the embryonic nucleus is located, gradually worsens and slowly expands to the periphery. It is light yellow in the early stages. As the opacity worsens, the color gradually deepens to dark yellow, dark brown, the density of the nucleus increases, and the refractive index increases. Patients often complain that their presbyopia has decreased or their myopia has increased. In the early stages, the peripheral cortex is still transparent. Therefore, the pupil dilates and vision improves in the dark, but the pupil constricts and vision deteriorates in strong light. Therefore, surgery is generally performed without waiting for the cortex to become completely opaque.

3. Posterior subcapsular cataract

The opacity is located in the subcapsular cortex of the lens. If it is located in the visual axis area, it will affect vision at an early stage.

What are the causes of cataracts? They can be divided into different types according to different causes.

One is senile cataract: the main type of cataract. It accounts for more than 80% of cataract patients, mostly in the elderly over 50 years old, and senile degenerative changes are the main cause;

The second is congenital cataracts; opacities in the lens are present at birth, caused by genetic factors or maternal viral infection or drug poisoning in early pregnancy;

The third is traumatic cataract: cataract caused by severe eye trauma, penetrating radiation, or occupational poisons that cause lens damage;

Fourth, concurrent cataract: lens opacity caused by eye disease or systemic disease is called concurrent cataract. Conditions such as uveitis, glaucoma, and diabetes can all be complicated by cataracts.

By understanding the above-mentioned causes of cataracts and normal clinical conditions, we can take comprehensive measures to prevent cataracts in our lives and better protect our eyes. Of course, when cataracts are caused by something we don’t realize, we must make sure to go to the hospital for examination and treatment in time, because cataracts are a relatively serious disease. If not treated in time, it may cause unnecessary damage to both eyes, and in severe cases it may even lead to blindness of both eyes.